Police said they believe Karl Nussbaum beat and choked his father, possibly even pistol-whipping him with a hand gun. However, police warned the preliminary autopsy results from Dallas were not yet available on Monday. So, his cause of death is technically unclear.Police believe the attack happened at Harold Nussbaums apartment, which is located on South McKinney Street in Mexia. Karl Nussbaum had been living there with his dad for roughly two months, as the result of a divorce, police said.But as police investigated his disappearance, they realized Karl Nussbaum was wanted on unrelated burglary warrants in Austin. When they arrested and questioned him, investigators said Karl Nussbaum gave up details about his dads death and led them to the body.Karl Nussbaum was sent to the Limestone County Jail in Groesbeck. His case will be handled by prosecutors with the Limestone County District Attorneys Office. If tried and convicted, Karl Nussbaum could face life in prison.